intervertebralis

The intervertebralis, also known as the discus intervertebralis or intervertebral disc, is a fibrocartilaginous structure that sits between adjacent vertebral bodies in the vertebral column. It acts as a joint and a cushion, transmitting load from one vertebra to the next while allowing limited movement and helping to absorb mechanical shocks.

Structurally, the disc has two main components. The outer annulus fibrosus consists of concentric lamellae of collagen and fibrocartilage that restrain the inner core and provide strength in multiple directions. The inner nucleus pulposus is a gel-like, proteoglycan-rich material with high water content that distributes pressure evenly and enables elasticity. The disc attaches to the adjacent vertebral endplates, through which nutrients diffuse.

Nutrition and longevity: Intervertebral discs are avascular in their inner regions; nutrients reach the cells by diffusion from the vascularized endplates and adjacent vertebral bodies. With aging, the nucleus pulposus loses water content and the disc height decreases, contributing to reduced flexibility and potential degeneration.

Function and pathology: The disc provides load transmission and enables bending and twisting movements. Degenerative disc disease, disc dehydration, or herniation of the nucleus pulposus through a damaged annulus fibrosus can compress adjacent nerves or the spinal cord, causing pain and neurological symptoms. Other conditions include discitis and, in some cases, tumors or infection.

Diagnosis and treatment: Magnetic resonance imaging is commonly used to assess disc structure and pathology. Treatment ranges from conservative approaches—physical therapy, analgesics, and injections—to surgical options such as discectomy or spinal fusion in refractory cases.